United Kingdom Size Standard to US: Slim / 49mm

United Kingdom Size Standard: Corresponds to a nominal width of 52 $\text{mm}$ (2.05 $\text{in}$), length of 185 $\text{mm}$ (7.28 $\text{in}$), average structural girth of 104 $\text{mm}$ (4.09 $\text{in}$), and fit category Standard / Regular.

US: Slim / 49mm: Corresponds to a nominal width of 49 $\text{mm}$ (1.93 $\text{in}$), length of 175 $\text{mm}$ (6.89 $\text{in}$), average structural girth of 98 $\text{mm}$ (3.86 $\text{in}$), and fit category Snug / Close.